Various types of ambient condition monitoring systems are known. These include fire monitoring systems. Such systems usually include a common control unit, or panel which communicates via a wired or wireless medium, or both, with a plurality of ambient condition detectors such as smoke detectors, fire detectors, gas detectors or the like. Output devices such as horns, sounders or strobes can be coupled to the control unit via the same, or, a second, different medium.
Current fire detectors can be considered mainly as input devices, since they collect information from the environment and transmit it to the control panel. Their ability to interact with the environment, for example giving an audible message in case of alarm, is very limited, unless special combined devices (detectors with integrated sounder, strobes or both) or dedicated stand alone sounder/strobes are used.
Usually just 1 or 2 LEDs (light emitting diodes) are available as outputs. They have a limited number of states: steady on, steady off, blink whenever a valid communication has been received. Some detectors have another output, called “remote output”, where the user can connect a load (typically an external LED) that can be controlled by the control panel in the same way as the detector's LED.
So the possibility for driving the user loads directly by the detector is very limited, just switching the output device on or off. With current systems, if it is necessary to install both a detector and an audio/visible device in a room (for example in a hotel room), either a combined device can be chosen (expensive both for the end user and the manufacturer) or a detector, a sounder and a strobe (or a combined sounder/strobe) must be installed (expensive for the user, increases system complexity for the control panel). It would be desirable to be able to reduce the cost and time of making such installations.
FIG. 1 illustrates a prior art system 10 which includes a system control unit or panel 12. Unit 12 could be implemented with one or more processors 12a and associated control software 12b. 
System 10 includes a plurality of detectors 20, of which 20i is a member. These detectors communicate with the unit 12 via a bidirectional communications medium 14. Detectors, such as 20i include a remote output port which via a wire 22 can be used to drive an LED 24 as discussed above.
FIG. 2 illustrates additional details of detector 20i. The detector 20i can include a programmable processor or microcontroller 26-1 and associated control software. An internal power supply 26-2 can be energized via the medium 14, conductors 14a,b. A switch 26-3 under control of circuits 26-1 can be used to energize the LED 24 via conductor 22.
The signal on line 22 can be an intermittently applied voltage which causes the load 24 to blink and provide a visual status output.